Power operated hand tool of the rotary impact type



F. A. KAMAN Se t. 6, i966 POWER OPERATED HAND TOOL OF THE ROTARY IMPACTTYPE Filed Oct. 28, 1963 5 Sheets-Sheet 1 INVENTOR.

FRANK A. ffA/WA/V JTTOKP/VEYS F. A. KAMAN Sept. 6, 1966 POWER OPERATEDHAND TOOL OF THE ROTARY IMPACT TYPE Filed 001,. 28, 1963 5 Sheets-Sheet2 INVENTOR. FRANK A. HAM/4N Sept. 6, 1966 F. A. KAMAN 3,270,593

POWER OPERATED HAND TOOL OF THE ROTARY IMPACT TYPE Filed Oct. 28, 1965 5SheetsSheet 5 INVENTOR. FRANK A. KAM/Q/V United States Patent 3,270,593POWER OPERATED HAND TOOL OF THE ROTARY IMPACT TYPE Frank A. Kaman,Prospect Heights, 11]., assignor to Skil Corporation, Chicago, Ill., acorporationof Delaware Filed Oct. 28, 1963, Ser. No. 319,449 2 Claims.(Cl. 81-52.3)

This invention relates to power tools, and more particularly to a newand improved power operated hand tool of the rotary impact type.

The present invention relates to the type of tool ineluding a motordriven impact clutch mechanism which automatically engages anddisengages in a rapid manner to deliver -a succession of rotationalhammer or impact blows to a driven member for running or loosening nuts,for example. This type of tool, often referred to as an impact wrench,is well known in the art.

In the vast majority of known impact tools, the impact clutch and therotary motor means for driving the former, are arranged in a toolhousing in axial alignment with each other. In other words, in this formof tool the axis of rotation of the impact clutch is coaxial with theaxis of rotation of the motor. While this form of tool is satisfactoryfor operating in many installations, it has the disadvantage of notbeing able to be manipulated in confined locations because of itsrelatively long length which results from the impact clutch and motorbeing in axial alignment with each other.

This disadvantage of this known form of impact wrench has become muchmore serious in recent years because of the ever increasing complexityof mechanical equipment, such as automobiles, which has resulted in agreater number of threaded fasteners forming a part of this equipmentbeing located in confined locations thereby making these fastenersinaccessible to known forms of power tools unless special attachmentdevices are used.

Attempts have been made to design impact wrenches of sufficient size fordeveloping the required magnitude of impact blows but yet of a size andshape which will adapt these tools for operating in confined locations.A tool which has been designed with this concept in mind is shown in theLarson et al. Patent 2,581,033. In the Larson et al. tool the axis ofrotation of the impact clutch is disposed at a right angle to theaxis-of rotation of the rotary motor means. This form of impact wrenchhas not achieved commercial success and is not on the market at thepresent time. The main reasons for this lack of commercialsuccess arethat a right angle relationship between the respective axes of rotationof the impact clutch and motor means has not achieved the desired spacesaving objective and that problems have arisen in providing a suitableright angle drive between the impact clutch and motor means withoutnecessitating an increase in the size of the tool for the purpose ofaccommodating the angular drive means.

Other prior art impact tools have provided angle drive means at theoutput end of the impact clutch. This type of tool comprises anattachment which includes suitable gearing means for transmitting therotary impact blows to a nut or the like having its axis of rotationangularly disposed with respect to the axis of rotation of the impactclutch. When using this type of angle attachment, the impact blow is notdelivered directly to the nut but is delivered to the latter through thegears of the angle attachment. Transmission of the impact blows throughthese gears causes a substantial reduction, e.g., 75%, of the impactforce, as tests have, proved. Further, the life of the gearsin these,attachments is rather short as the impact blow is absorbed by only onegear tooth or at the most 1.1% of the total teeth in the gear, therebycaus- 3,270,593 Patented Sept. 6, 1966 ice ing breakage of these teeth.Because of these disadvantages, angle attachments for impact tools havenot proved to be satisfactory.

Accordingly, it is a primary objective of the present invention toprovide a new and improved power operated impact wrench wherein theimpact clutch and the rotary motor means therefor are mounted withrespect to each other in a unique angular relationship resulting in animpact tool of minimum size in relation to its impact clutch and rotarymotor which are of a given size.

Another object of the present invention is the provision of a power toolof the type described wherein the impact clutch and rotary motor meanstherefor are mounted with respect to each other in a unique angularrelationship so as to permit the angular drive between the motor and theimpact clutch to be of uncomplicated and compact construction.

Still another object of the present invention is the provision of a toolof the type described having a housing which includes an impact clutchenclosing head portion and a rotary motor enclosing handle portion, thehead portion being angularly disposed with respect to the handle portionfor maintaining the over-all length of the tool at a minimum withoutallowing the head portion to project an objectionable distance beyondthe laterial extremities of the handle portion.

Even another object of the present invention is the provision of a toolof the type described which includes an impact clutch having a rotarydriven member or anvil which is journaled at its output end in one endof the head portion of the tool, the anvil being provided with a toolreceiving socket in its output end.

Yet another object of the present invention is the provision of a newand improved socket tool for use with a power tool of the typedescribed, which socket tool is specially adapted for running nuts onstud bolts or the like.

Still another object of the present invention is the provision of a newand improved socket tool for use with a power tool having a rotarydriven member which is provided with a tool receiving socket, whichsocket tool has one end thereof adapted for being detachably received inthe tool receiving socket for making a driving engagement between thesocket tool and the rotary driven member and the other end thereofadapted for making a driving engagement with a nut or the like, andwhich socket tool is provided with a central, axially extending, throughbore for allowing entry of a stud bolt thereby adapting the socket toolfor running a nut a substantial distance along a stud.

These and other objects and advantages of the invention will becomeapparent from the following specification describing a preferredembodiment of the invention which is illustrated in the accompanyingdrawings.

In the drawings:

FIG. 1 is a longitudinal central section taken through a power operatedhand tool of the rotary impact type constructed according to the presentinvention;

FIG. 2 is a perspective view of the power tool being held in a humanhand;

FIG. 3 is a reduced top plan view of the tool;

FIG. 4 is a side elevational view of the tool showing the same beingheld in a human hand;

FIG. 5 is a bottom plan vie-w of the tool;

FIG. 6 is an enlarged fragmentary view, partially in section andpartially in side elevation, of the power tool and socket tool thereforwhich forms a part of the present invention;

FIG. 7 is a fragmentary view, partially in section and partially in sideelevation, of the socket tool aligned with the tool receiving socket ofthe rotary driving member of 3 the power tool for being engaged indriving relation with the latter;

FIG. 8 is a side elevational view of the socket tool;

FIG. 9 is an end elevational view of the socket tool as seen from thetop thereof; and

FIG. 10 is an end elevational view of the socket tool as seen from thebottom thereof.

By way of introduction, the power operated hand tool of this inventionincludes a housing having a generally cylindrical, impact clutchenclosing, head portion and an integral, elongated, generallycylindrical, rotary motor enclosing handle portion. The impact clutchextends longitudinally of the cylindrical head portion and has itsoutput end disposed adjacent one end of the head portion of the housingwhich may be termed the nose of the power tool. The head portion andhandle portion of the housing are angularly disposed with respect toeach other so that respective central longitudinal axes of theseportions intersect and an obtuse angle is defined by the nose of thehead portion, the point of intersection of the housing portion axes, andthe free end of the handle portion. This angular disposition between thehead portion and handle portion of the tool serves to permit the powertool to be of smaller and more comp-act construction for at least tworeasons which will become apparent from the following description.

First, taking an impact clutch and a rotary motor of given size andenclosing these components in close confining relation in respectivehead and handle portions of a housing inclined with respect to eachother in the manner described, the over-all length of such a tool may beno greater than a power tool which utilizes a right angle relationshipbetween the axes of rotation of the impact clutch and rotary motor.However, the distance either of the ends of the head portion projectbeyond lateral extremities of the handle portion will be less because byusing the angular relationship according to this invention opposite endsof the head portion project beyond lateral extremities of the handleportion thereby reducing the distance one of the ends of the headportion projects beyond a lateral extremity of the handle portion. Inother words, by inclining the head and handle portions of the housing.in the manner according to this invention which brings about projectingrespective opposite ends of the head portion beyond the lateralextremities of the handle portion, the distance the nose of the headportion projects from the lateral extremity of the handle portion ismuch less than would result if, for example, a right angle relationshipis employed between the head and handle portions of the power tool.

Ssecondly, by employing the angular relationship of this invention, theresulting power tool may be smaller and more compact since the gearingbet-ween the motor and impact clutch may be of smaller and simplerconstruction. By using the angular relationship according to the presentinvention, ordinary bevel gears may be utilized to make up the angulardrive between the motor and the impact clutch, and these bevel gears maybe of a diameter no greater than the diameters of the rotary motor orcylindrical hammer which constitutes a major portion of the impactclutch. As will become apparent from the following specification, if,for example, a right angular relationship is employed between the impactclutch and rotary motor, at least one of the gears making up thisangular drive must be of a diameter greater than the diameter of thehammer of the impact clutch.

This angular constructional feature is of significance as it permits aspecific embodiment of the power tool to be constructed so that the noseof the head portion is in general alignment with the knuckles of a humanhand grasping the handle portion of the tool, which relationship wouldnot be possible if a right angle drive was used with the sizes of theimpact clutch and motor being held constant. Manifestly, this isimportant when operating the tool in confined locations as it permitsthe tool to be manipulated in any location which is large enough topermit entry of a human hand. i

The power tool of this invention also includes the provision ofproviding a socket in the output end of the rotary driven member oranvil forming a part of the impact clutch, which end is journaled in thenose of the head portion of the tool. The provision of this socket inlieu of the conventional driving square which projects from the outputend of the impact clutch permits the over-all length of the impactclutch to be reduced thereby resulting in a power tool of reduced andcompact size. Further, the invention includes a provision of a sockettool adapted for cooperating with the socket in the rotary drivingmember of the impact clutch for running nuts on stud bolts in confinedlocations. j

Now referring to the drawings, the power operated hand tool of thisinvention, generally designated -10, includes an elongated, generallycylindrical handle portion 12and an integral generally cylindrical'headportion 14'. Handle portion 12 encloses a reversible pneumatic motor 15which extends longitudinally of the handle portion. Motor '15 includes acylindrical stator 16 enclosing a plurality of vanes 17 which aremounted on a shaft 18 having one of its ends mounted in a ball bearingassembly 19. The central axis of shaft 18 isco-axial with an axis 20which defines the longitudinal central axis of housing portion 12. Theother end of shaft 18 is supported in a hub portion 22 of a bevel gear23, which hub portion is rotatably mounted in a ball bearing assembly24. Shaft 18 includes a splined portion 18a atone of its ends which isfitted in a central splined bore in bevel gear 23 fornon-rotatablysecuring the bevel gear on shaft 18.

Handle portion 12 includes a control valve assembly 26 at the free endthereof, which control valve may be of the type disclosed in theapplication of Carl J. Frenzel, Serial No. 293,501, filed July 8, 1963now Patent No. 3,202,183. It will be understood that the control valveassembly acts to permit a pressurized fiuid, such as air, to be admittedto motor 15 in either one of two opposite flow paths for bringing aboutrotation of the motor in either a forward or reverse rotary direction.

Briefly, the control valve assembly includes a fitting 27 threadinglysecured in a housing member 28 which is secured to the free end ofportion 12 by a plurality of fasteners 28a (FIGS. 3 and 4). Fitting 27includes a central threaded bore 29 adapted for threading engagementwith a suitable fitting on one end of an air conduit, for example. Thecontrol valve primarily includes a plunger 31 reciprocal in aselectively rotatable plug 32, which plug may be rotated from theexterior of the power tool by a plate 33 for changing the direction ofthe flow path of air admitted to motor 15 for changing the direction ofrotation of the latter. Plunger 31 is reciprocated for admitting airinto motor 15 by means of an operating lever 34 which includesspaced-apart ear plate portions 35 at one of its ends, which portionsare 'apertured for receiving a pin 36 thereby adapting the operatinglever for swinging or pivoting movement relative to handle portion 12.The operating lever is held in its outer or closed position, indicatedin solid lines in FIG. 1, by engagement of the outer end of plunger 31with the operating member, the plunger being urged outwardly of the toolby means of a coil spring 38. The inner or open position of theoperating lever is indicated in phantom lines in FIG. 1. Means operatedby a knob 39 are provided for controlling the rate of fluid admitted tomotor 15 thereby to control the speed of the latter.

It should be understood that the" power tool of this invention is not tobe limited to the particular'motor and control means shown. Any smalland compact motor and control means which may beeasily enclosed withinelongated handle portion 12 may be employed.

Generally cylindricalhousing head portion 14 encloses in close confiningrelation'an impact clutch generally designated 40. Impact clutch 40maybe of the type disclosed in Kaman et al. application, Serial No.222,868, filed September 11, 1962, now Patent No. 3,228,486. This impactclutch includes a cylindrical hammer 41 adapted for rotation about itscentral axis which is co-axial with an axis 42 defining a longitudinalcentral axis of head portion 14. An anvil 43 is rotatably mounted withinhammer 41 by roller bearing assemblies 44 and 45 which are spaced alongthe length of a shank portion 46 of anvil 43. Hammer 41 carries a pairof jaw pins 48 which are slidably mounted in the hammer for movementaxially of the latter, the pins being urged in one direction by coilsprings 51 for non-interfering relation with diametrically oppositelydisposed anvil arms 50. A series of circular cams 53, 54 and S5 operableby means of relative rotation between the anvil and the hammer areprovided for periodically projecting pins 48 into a position where theywill simultaneously engage arms on the anvil for delivering a sharprotary impact blow to the latter.

It will be understood that the impact clutch mechanism of itself formsno part of the present invention. Any impact clutch mechanism of compactdesign may be employed in the powered hand tool of this invention.

Hammer 41 includes a reduced-in-diameter neck portion 58 which mounts abevel gear 60. Bevel gear 60 is concentrically located on hammer 41 andis non-rotatably secured thereto as by means of a key (not shown), forexample. The upper end of the barrel terminates in a hub 61, which hubis of smaller diameter than the diameter of portion 58 and extendsaxially from the latter.

Hub 61 is rotatably mounted in a ball bearing assembly.

62 which is suitably supported in a circular recess 63 formed in an endhousing wall member 64 defining one end of housing portion 14, thehousing wall being secured in place by a plurality of fasteners 65.

The end of the anvil defining the output end of the impact clutch is inthe form of a cylindrical extension 66 which is journaled in a sleeve'67. Sleeve 67 is nonrotatably mounted in a ring member 68, which ringmember is affixed to the nose of cylindrical housing portion 14.

It will be understood that anvil 43 is mounted for rotation within headportion 14 for being given sharp impact blows in rapid succession uponactuation of impact clutch 40, actuation of the impact clutch beingbrought about by periodic relative rotation between the hammer and anvilin a manner known in the art. Rotation of hammer 41 of the impact clutchresults upon rotation of bevel gear 66! which defines the input end ofthe impact clutch. Rotation of bevel gear 60 is accomplished by rotationof motor 15 by meshing engagement of the teeth of bevel gear 60 with theteeth of bevel gear 23.

As noted in FIG. 1, longitudinal central axes 20 and 42 of respectivehousing portions 12 and 14 intersect at a point A which is intermediatethe input and output ends of the impact clutch. The angular dispositionof these axes with respect to each other is such that an obtuse angle isdefined between the nose of head portion 14, point A and the free end ofhandle portion 12, this angle being indicated as B. Angle B may be inthe range of 95 to 155. Preferably, this angle includes 112, this beingthe angle illustrated in the figures in the drawings.

By further reference to FIG. 1, it will be seen that the cone (indicatedby lines 71) containing the pitch surface of bevel gear 69 has its apexat point A. Further, the cone (indicated by lines 72) containing thepitch surface of bevel gear 23 also has its apex at point A. Thisconstructional feature of having the apexes of the cones containing thepitch surfaces of respective bevel gears lying at a common point permitsthe bevel gears to be of minimum size and yet of ordinary orconventional construction, i.e., larger gears or specially machinedbevel gears are not required. It will be noted from FIG. 1 that thediameter of bevel gear 60 at its area of maximum diameter does notexceed the diameter of cylindrical hammer 41. Further, it will be notedthat the diameter of bevel gear 23 at its area of maximum diameter doesnot exceed the diameter of rotary motor 15.

That the angular disposition of respective housing axes 2t) and 42according to this invention permits bevel gears constituting the angulardrive between the motor and impact clutch to be of minimum size and ofconventional construction can be understood and appreciated byconsidering the gearing that would be necessary if axis 42 of headportion 14 was disposed at a right angle with respect to handle portionaxis 20, i.e., if angle B was 90. If this relationship was utilized,cylindrical hammer 41 of the impact clutch would be mounted as close aspossible to bevel gear 23 in the interest of compact design. It will bereadily apparent then that bevel gear 60 would have to be of a diametergreater than the diameter of cylinder 41 to bring about meshingengagement of the teeth of bevel gear 60 with the teeth of bevel gear23. Increasing of the size or diameter of bevel gear 60 beyond thediameter of hammer 41 is of course objectionable as this wouldnecessitate a power tool of increased over-all size. If on the otherhand, this 90 relationship was utilized but bevel gear 60 was of adiameter equal to or less than the diameter of cylindrical hammer 41,bevel gear 23 would have to be of greatly increased size and of unusualshape so as to mesh with gear 60 and yet clear the outer extremities ofcylindrical hammer 41.

It should now be apparent that by inclining the impact clutch withrespect to the rotary motor in the manner according to the presentinvention, bevel gears 23 and 60 may be of conventional construction,bevel gear 23 may be of a diameter not greater than the diameter of themotor 15 and bevel gear 16 may be of a diameter not greater than thediameter of cylindrical hammer 41. Manifestly this permits theconstruction of a power tool of small and compact size. Further, itshould be noted that this constructional feature of the tool permitsbevel gears 23 and 60 to be of substantially the same diameter forproviding an approximate 1:1 drive ratio between the motor and impactclutch, which ratio is desirable in impact tools of the type utilizingan air motor as is known to those skilled in the art.

In obtaining this approximate 1:1 drive ratio, it is preferable toprovide a slight difference between the total number of teeth on gear 23and gear 60 so that the rebound force developed by the impact clutchafter every rotary impact blow will be imparted to different pairs ofmeshing teeth during any series of repeated impact blows. If the samenumber of teeth are provided on both gears 23 and 60, the same pair orpairs of meshing teeth would be subjected to the rebound forces duringany one series of impact blows. A difference of one tooth between thetotal number of teeth on gears 23 and 6th is sufficient, and thisdifi'erence or a difference of two or three teeth is intended by theexpression an approximate 1:1 drive ratio.

It should also be appreciated that the provision of obtuse angle Bbetween axes 2t) and 42 results in the nose of head portion 14projecting a shorter distance from the lateral extremity of handleportion 12, i.e., the underside of the handle portion as viewed in FIG.1, than would be the case if a right angle relationship was employedbetween axes 20 and 42. Manifestly, if such a right angle relationshipwas utilized and if the diameter of bevel gear 23 was not increased,bevel gear 60 would be lowered from its position illustrated in FIG. 1thereby resulting in lowering of the output end of the impact clutchassuming the length of the impact clutch to be constant. It is of coursedesirable to keep the distance between the underside of handle portion12 (asillustrated in FIG. 1) and the nose of head portion 14 to aminimum to achieve the design objective of compact construction.

As illustrated in FIGS. 2 and 4 and especially in FIG. 4, according tothe construction of the power tool of this invention the nose of headportion 14 is in general alignment with the knuckles of a human hand 75which is grasping handle portion 12 of the power tool. This featurepermits the power tool to be operated in almost any location largeenough to accommodate a human hand grasping the tool. In other words, byreason of the angular relationship of axes 20 and 42, the rotary motormeans and impact clutch may be enclosed within respective housingportions 12 and 14 so that the nose of the latter is in generalalignment with the knuckles of a human hand and the motor means andimpact clutch may be of greater size than would be possible if a rightangle relationship was used and the nose of the head portion maintainedin alignment with the knuckles of a hand grasping the handle portion ofthe tool.

The concept of compact design is further eflectuated according to thepresent invention by providing rotary driven member or anvil 43 with atool receiving socket 76 in cylindrical portion 66 of the anvil. Toolreceiving socket 76, which is preferably hexagonal in shape andterminates in an annular recess 77, is folded or disposed within theportion of the anvil which is journaled in sleeve 66 forming a part ofthe nose of head portion 14. Tool receiving socket 76 is provided inlieu of the conventional driving square which would project from thenose of the head portion of the power tool.

The present invention also includes a novel socket tool which uniquelycooperates with tool receiving socket 76 for running nuts in confinedlocations and particularly for running nuts on stud bolts in confinedlocations.

The socket tool of this invention (FIGS. 6-10), generally designated 80,includes a generally cylindrical body 81. Body 81 is provided at one end82 thereof with a multisided (preferably hexagonal) exterior shape whichcorresponds in size and shape to tool receiving socket 76 in anvil 43.Body end 82 includes an exterior annular recess 83 adapted to receive aretainer member such as an O-ring or steel snap-ring 84.

The other or opposite end of body 81 is provided with a multi-sided(preferably hexagonal) socket-opening 85, which socket-opening isadapted to receive a nut or the like for making a driving engagementwith the same. Body 81 further includes a central, axially extendingthrough bore 86 which opens at one end thereof into socket-opening 85and which opens at the other end thereof at body end 82. Body 81 is alsoprovided with an outer knurled circular band 87 which adapts the sockettool to be easily gripped for being inserted in a tool receiving socketor for being removed from a tool receiving socket.

Socket tool 80 is attached to the power tool in a driving relation withthe latter by inserting body end 82 into tool receiving socket 76 ofanvil 43, retainer member 84 frictionally engages the sides of toolreceiving socket 76 for securely holding the socket tool in the toolreceiving socket but for permitting the socket tool to be readilydetached by hand from the anvil. By reason of the complementaryengagement of multi-sided tool receiving socket 76 with multi-sided bodyend 82, it will be apparent that rotation of the anvil will causerotation of the socket tool for driving of the latter.

The socket tool of this invention is adapted for running nuts on boltsor driving cap screws, and the socket tool is especially adapted forrunning nuts on stud bolts in confined locations.

In FIG. 6, tool socket 80 is shown engaged with a nut 90 threadinglyengaged on a stud bolt 91 projecting from a workpiece 92. Nut '90 isreceived in body socket-opening 85 in driven relation with the same. Itwill be apparent that nut 90 may be run a substantial distance alongstud 91, as the stud is permitted to enter tool socket bore 86 duningrunning of the nut. The feature of providing the socket tool withaxially extending bore 86 opening at one end thereof into socket-opening85 and opening at the other end thereof at body end 82 adapts the sockettool for receiving a portion of a stud as a nut is being run on the sameby the socket tool. Accordingly, by the use of socket tool 80 a nut maybe run on a stud for a considerable distance along the length of thestud. Heretofore, it has been necessary to employ tools of the endwrench type or special deep sockets to run nuts a considerable distancealong a stud bolt. These devices add considerably to the length of thetool and socket combinations and are difficult or impossible to use inconfined spaces.

It will also be apparent that socket tool '80 cooperates with thesocketed anvil for running a nut on a stud in an environment wherein thestud is disposed in a confined location. This is brought about by thenovel cooperation between tool receiving socket 76 and socket tool 80which results in substantial shortening of the over-all longitudinallength of the head portion 14 and socket tool 80 secured thereto. As isapparent from FIG. 6, since body end 82 is received within socket 76 inthe anvil, stud 91 which is allowed to enter bore 86 actually extendsinto the nose of the power tool itself. In other words, an over-allspace saving design concept is made possible by allowing a substantialportion of the stud to enter within the power tool itself as a nut isbeing run on the stud by the socket tool of this invention. Manifest-1y, this feature permits the socket tool of this invention and the powertool to run many nuts which are inaccessible when employing prior aresocket tools not having special attachments.

It will be apparent that body end 82 maybe shaped or designed toaccommodate a particular tool receiving socket of a rotary drivingmember or anvil. Also, it will be apparent that socket-opening 85 may beprovided in sizes and shapes for accommodating a particular nut or thelike to be run.

While the invention has been shown in but one form it will be obvious tothose skilled in the art that it is not to be so limited, but on theother hand it is susceptible of various changes and modificationswithout departing from the spirit and scope of the appended claims.

I claim:

1. A power operated hand tool of the rotary impact type comprising, ahousing including a handle portion having a longitudinal central axisand a head portion having a longitudinal central axis, rotary motormeans in said handle portion extending longitudinally of the latter, afirst bevel gear driven by said motor means at one end thereof and beingdisposed adjacent one end of said handle portion, which bevel gear hasits axis of rotation co-axial with said axis of the handle portion andhas its maximum diameter no greater than the diameter of the rotarymotor means, the apex of the cone containing the pitch surface of saidfirst ibevel gear being disposed outwardly of said one end of the handleportion, rotary impact clutch means including a cylindrical hammer insaid head portion extending longitudinally of the latter, which impactclutch means has an input end and an output end, a second bevel geardefining said input end and being disposed adjacent one end of said headportion, which second bevel gear has its axis of rotation co-axial withsaid axis of the head portion and has its maximum diameter no greaterthan the diameter of said impact clutch means, the apex of the conecontaining the pitch surface of said second bevel gear being disposedintermediate said input and output ends and being coincident with saidfirst mentioned apex, said first and second bevel gears being in meshingengagement with their respective axes of rotation intersecting at thepoint defined by both of said apexes, the portions of the last mentionedaxes between the intersection thereof and respective gears defining anangle in the range of 68, said output end being defined by a drivingmember having a socket opening at the other end of said head portion andbeing substantially contained within the latter, said handle portionbeing in close confining relation with said motor means and first bevelgear and said head portion being in close confining relation with saidimpact clutch and second bevel gear, said handle portion being elongatedalong the longitudinal central axis thereof and being of a size suchthat a substantial portion of the same can be received between thefingers and palm of a human hand, said head portion 'being elongatedalong the longitudinal central axis thereof and being of a size suchthat said output end is in general alignment with the extremities of theknuckles of a human hand grasping the tool in the manner set forth.

2. The power tool according to claim 1 wherein said first bevel gearincludes a concentric cavity in the face there-of adjacent said impactclutch, and wherein a portion of said cylindrical hammer is receivedWithin said cavity.

References Cited by the Examiner UNITED STATES PATENTS 10 Church 8157 XGla'baznya 81-57 Sayer 81212.1 X Fosnot. Larson et al. 8152.3 Waterval81121.1 Coffman et -al. Reynolds 81121 Stumpf 81121 Sindelar 81-523Schadlich 81-523 MILTON S. MEHR, Examiner.

J. L. Jones, .IR., Assistant Examiner.

1. A POWER OPERATED HAND TOOL OF THE ROTARY IMPACT TYPE COMPRISING, AHOUSING INCLUDING A HANDLE PORTION HAVING A LONGITUDINAL CENTRAL AXISAND A HEAD PORTION HAVING A LONGITUDINAL CENTRAL AXIS AND A HEAD PORTIONHAVSAID HANDLE PORTION EXTENDING LONGITUDINALLY OF THE LATTER, A FIRSTBEVEL GEAR DRIVEN BY SAID MOTOR MEANS AT ONE END THEREOF AND BEINGDISPOSED ADJACENT ONE END OF SAID HANDLE PORTION, WHICH BEVEL GEAR HASITS AXIS OF ROTATION CO-AXIAL WITH SAID AXIS OF THE HANDLE PORTION ANDHAS ITS MAXIMUM DIAMETER NO GREATER THAN THE DIAMETER OF THE ROTARYMOTOR MEANS, THE APEX OF THE CONE CONTAINING THE PITCH SURFACE OF SAIDFIRST BEVEL GEAR BEING DISPOSED OUTWARDLY OF SAID ONE END OF THE HANDLEPORTION, ROTARY IMPACT CLUTCH MEANS INCLUDING A CYLINDRICAL HAMMER INSAID HEAD PORTION EXTENDING LONGITUDINALLY OF THE LATTER, WHICH IMPACTCLUTCH MEANS HAS AN INPUT END AND AN OUTPUT END, A SECOND BEVEL GEARDEFINING SAID INPUT END AND BEING DISPOSED ADJACENT ONE END OF SAID HEADPORTION, WHICH SECOND BEVEL GEAR HAS ITS AXIS OF ROTATION CO-AXIAL WITHSAID AXIS OF THE HEAD PORTION AND HAS ITS MAXIMUM DIAMETER NO GREATERTHAN THE DIAMETER OF SAID IMPACT CLUTCH MEANS, THE APEX OF THE CONECONTAINING THE PITCH SURFACE OF SAID SECOND BEVEL GEAR BEING DISPOSEDINTERMEDIATE SAID INPUT AND OUTPUT ENDS AND BEING COINCIDENT WITH SAIDFIRST MENTIONED APEX, SAID FIRST AND SECOND BEVEL GEARS BEING IN MESHINGENGAGEMENT WITH THEIR RESPECTIVE AXES OF ROTATION INTERSECTING AT THEPOINT DEFINED BY BOTH OF SAID APEXES, THE PORTIONS OF THE LAST MENTIONEDAXES BETWEEN THE INTERSECTION THEREOF AND RESPECTIVE GEARS DEFINING ANANGLE IN THE RANGE OF 68*, SAID OUTPUT END BEING DEFINED BY A DRIVINGMEMBER HAVING A SOCKET OPENING AT THE OTHER END OF SAID HEAD PORTION ANDBEING SUBSTANTIALLY CONTAINED WITHIN THE LATTER, SAID HANDLE PORTIONBEING IN CLOSE CONFINING RELATION WITH SAID MOTOR MEANS AND FIRST BEVELGEAR AND SAID HEAD PORTION BEING IN CLOSE CONFINING RELATION WITH SAIDIMPACT CLUTCH AND SECOND BEVEL GEAR, SAID HANDLE PORTION BEING ELONGATEDALONG THE LONGITUDINAL CENTRAL AXIS THEREOF AND BEING OF A SIZE SUCHTHAT A SUBSTANTIAL PORTION OF THE SAME CAN BE RECEIVED BETWEEN THEFINGERS AND PALM OF A HUMAN HAND, SAID HEAD PORTION BEING ELONGATEDALONG THE LONGITUDINAL CENTRAL AXIS THEREOF AND BEING OF A SIZE SUCHTHAT SAID OUTPUT END IS IN GENERAL ALIGNMENT WITH THE EXTREMITIES OF THEKNUCKLES OF A HUMAN HAND GRASPING THE TOOL IN THE MANNER SET FORTH.